OpenPLC-with-LDmicro/C3/CTC-Counter/English

Visual Cue	Narration
Slide 1:	Welcome to the spoken tutorial on CTC Counter
Slide 2: Learning Objectives Count circular(CTC) counter	In this tutorial, we’ll learn about working of Count circular counter.
Slide 3: System Requirements Ubuntu 18.04 OS LDmicro OpenPLC Mainboard 24V, 2A SMPS USBasp programmer Traffic Light module Switchboard module	To record this tutorial I am using: Ubuntu Linux 18.04 operating system LDmicro OpenPLC Mainboard 24V, 2A SMPS USBasp programmer Traffic Light module and Switchboard module
Slide 4: Pre-requisites Working of CTU and CTD counters If not, please refer to the relevant tutorials from Home | spoken-tutorial.org	To follow this tutorial, you should know the working of CTU and CTD counters. If not, please refer to the relevant tutorials in this series on this website.
Slide 5: Prerequisites - Hardware setup hardware-prerequisite.jpg	Connect SMPS and USBasp to the Mainboard as shown in the picture. Keep these connections throughout this tutorial.
Open the LDmicro	Let us open LDmicro.
	In this tutorial, we will create a ladder logic to turn on an LED. The condition is when the switch is pressed for exactly 3 times.
Click ‘Instructions -> Insert Contact’ Double-click on Xnew >> Type ‘switch’ in name box >> Click OK button	Insert a Contact and then rename it as ‘switch’ as shown.
Place the cursor to the right of Xswitch >> Click Instructions -> Counters -> Insert CTC	We will now insert a CTC to the right of Xswitch. For that place the cursor to the right of Xswitch. Click on Instructions, then Counters and then on ‘Insert CTC’.
Double-click on Cnew	Double-click on the CTC.
In the Name column, type count	We can observe there are two columns. First one is for the name of the counter. Type ‘count’ in it.
In the True if >= column type 3 Click the OK button	Second column is the Max value i.e. maximum value of the counter. Here, we have to enter the desired count value. We will enter 3 as the count value. Click on the OK button. Note that the name is prefixed by C by default.
Click Edit -> Insert rung below	Now, insert a rung below.
Place the cursor in the new rung >> Click Instructions -> Comparison operators -> Insert EQU Place the cursor to the right of EQU >> Click Instructions -> Insert Coil	Insert equals compare instruction in the new rung as shown. Place the cursor to the right of EQU and insert a Coil.
Double-click on EQU >> Type Ccount in the ‘Closed’ if column >> Type 3 in =: column >> Click the OK button	In the Compare instruction, compare Ccount with 3. That is, in the ‘Closed if’ column type Ccount and in the ‘equals’ column type 3.
Double click on the coil >> Rename it as ‘LED’ >> Click OK button	Rename the Coil as ‘LED’.
	We will now check the working of this logic.
Click Simulate -> Simulation mode >> Click Simulate -> Real-time simulation	Let us turn on the simulation mode. For that, click Simulate and then on Simulation mode. Next, start real-time simulation as shown.
Highlight the state of Xswitch, YLED and TON in the IO list	Initially the state of Xswitch, YLED and Ccount are 0.
Double-click on Xswitch in the IO list Highlight the state of Ccount	Change the state of Xswitch to 1 by double clicking on it. We can observe the Ccount value changes to 1. Change the state of Xswitch back to 0.
	Just like CTU and CTD, the Ccount value updates only with the rising edge of its input.
Double-click on Xswitch for 5 times Highlight the state of YLED	Keep double clicking on Xswitch until the state of Ccount reaches 3. We can observe the state of YLED changes to 1.
Double-click on Xswitch Highlight the state of Ccount	Once again change the state of Xswitch from 0 to 1. We can observe the Ccount value goes back to 0.
	That is there is no need of RESET instruction to reset the counter.
Click Simulate -> Halt Simulation >> Click Simulate -> Simulation Mode	Now, turn off the simulation mode. For that, click Simulate and then on Halt Simulation. Then click Simulate and Simulation Mode.
	Now let us compile the logic. The detailed steps on how to compile and save the logic are explained in the earlier tutorials.
Click on Settings >> Click on Microcontroller >> Select AVR ATmega16 40-PDIP Click on Settings >> Click on MCU parameters >> Change Crystal frequency to 16	Click on Settings and select the microcontroller AVR ATmega16 40-PDIP. Adjust its parameters as shown here.
Double-click on Xswitch in I/O list >> Select PC0 >> Click OK button Double-click on YLED in I/O list >> Select PA0 >> Click OK button	Assign pin PC0 to Xswitch and PA0 to YLED.
Click on Compile >> Click on Compile >> Go to Desktop/LDmicro folder >> Rename it as ‘ctc.hex’ >> Click on Save. Click OK button	Compile the logic as ctc.hex
Click on File >> Click on Save >> Go to Desktop/LDmicro folder >> Rename it as ‘ctc.ld’ >> Click on Save	Save the file as ctc.ld
	We will now see the working of this logic on hardware.
Connect Mainboard to PC using USBasp laptop-usbasp.jpg	Connect the Mainboard to your laptop using USBasp. Turn on the power supply.
Open terminal >> Type cd Desktop/LDmicro >> Press ENTER >> type ‘avrdude -c usbasp -p m16 -U flash:w:ctc.hex’ >> Press ENTER	Open the terminal by pressing CTRL+ALT+T keys simultaneously. Go to the folder where you have saved the hex file. Type the command as shown to upload the hex file to the Mainboard.
Remove the USBasp connection from the laptop.	Turn off the power supply. Remove the USBasp connection from the laptop. This will prevent any hardware damage.
ctc.png	Let us see the connection details now.
ctc.png >> connect as per the narration	Connect GND pin of the red LED of Traffic Light module to GND of the Mainboard. Then connect the +5V pin of the red LED to PA0 pin of the Mainboard.
ctc.png >> connect as per the narration	Connect GND and 5V of switchboard to GND and 5V of the Mainboard respectively. Then connect NO1 of the Switchboard to PC0 of the Mainboard. Make the connections as shown in the picture.
Turn on the power supply.	After making all the connections properly, turn on the power supply.
Point to red LED	Initially the red LED will not glow.
Press NO1 three times	It will glow only when NO1 is pressed for three times. So, press the NO1 for 3 times.
LED glows	We can see the LED will be glowing even after NO1 is released.
Press NO1	Press the switch NO1 for one more time. We can observe the LED goes off. Recall that it was not the case with CTU.
	That is CTC counter resets automatically after reaching the desired count value. Thus the difference between CTU and CTC is auto reset.
Turn off the power supply.	Turn off the power supply.
	This brings us to the end of this tutorial. Let us summarize.
Slide 7: Summary Count circular (CTC) counter	In this tutorial we learnt about working of Count circular counter.
Slide 8: Assignment Draw a ladder logic where the state of LED depends on switch press count count = 0, LED should RESET. count = 1, LED should start blinking count = 2, the LED should be SET	As an assignment, do the following. Draw a ladder logic where the state of LED depends on switch press count. That is, when count = 0, LED should RESET. count = 1 , LED should start blinking count = 2, the LED should be SET
Slide 9: About Spoken Tutorial project	The video at the following link summarises the Spoken Tutorial project. Please download and watch it
Slide 10: Spoken Tutorial workshops	The Spoken Tutorial Project team: conducts workshops using spoken tutorials and gives certificates on passing online tests. For more details, please write to us
Slide 11: Forum for specific questions:	Please post your timed queries in this forum
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Slide 13: Acknowledgement	Spoken Tutorial Project is funded by MHRD, Government of India.
Slide 14: Thank you slide	This tutorial has been contributed by FOSSEE and Spoken Tutorial Project, IIT Bombay. And this is Harsha Priyanka from FOSSEE team, signing off. Thanks for watching.

Contributors and Content Editors

Nirmala Venkat